I got this weird pop message from Microsoft Projects 2016 about calendar does not exist. Multiple projects hanging off a resource pool file. There is only one calendar and it is the standard one with a few holidays.
Use the Organizer (File, Organizer) and copied the Resource Pool calendar to the project calendar with the same effect.
Google says go search for corrupted calendars. One post says save a baseline.
And it was fixed.
Awesome, thanks ! The baseline fixed it
I did and … it pretended it saved, but then I lost all my modifications… not great experience